The majority of pet owners will have received numerous vaccinations themselves over the course of their lives. For most infectious human diseases, after an initial course as babies or young children no further vaccines are required; or maybe a single booster shot every decade or so. It can be hard to understand why our pets need much more frequent vaccination. And why, when those vaccinations lapse they sometimes need to restart the whole course.

The current climate has meant that many pets have had their yearly vaccination appointments cancelled or delayed. If your pet’s vaccinations are overdue by more than around 3 months, your veterinary surgeon is likely to recommend that your dog restarts their vaccination course. This generally means that they repeat the vaccination course that they had as a puppy – two injections usually 2-4 weeks apart. It can feel like there is lots of varying advice as to whether this is really necessary. But it comes down to just a few factors.

In the UK we recommend almost all dogs receive regular vaccinations against four major canine infectious diseases. These are Canine Parvovirus (CPV), Canine distemper virus (CDV), Canine adenovirus (CAV) and Leptospirosis. 

Core Canine Vaccinations: CPV, CDV and CAV are viral diseases and considered core vaccinations for all dogs around the world.

After vaccination for these three, a strong and long lasting immunity is produced in the majority of dogs. In most cases this lasts for a minimum of three years. Logically most veterinary professionals recommend booster vaccinations against these components every three years. This is actually quite a long time if you compare the relative life spans of humans and our canine friends. If your pet has gone over the three year mark for a vaccine against these three, a single booster injection should be sufficient to kick start their immunity and offer full protection.

Leptospirosis

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In the UK it is recommended that Leptospirosis is also considered a core vaccination as it is relatively common. Leptospirosis is a disease caused by a group of bacteria. It is usually caught from rats, farm animals or stagnant water contaminated by animal urine. The disease causes severe liver and kidney damage and in its most severe form can be fatal. It is also important as a zoonosis. This means that it is a disease that can be contracted by humans from animals. For these reasons it is very important to keep your pet’s leptospirosis vaccinations up to date. 

The problem with leptospirosis vaccines is that they do not produce the same long lived immunity as the viral infections we vaccinate against. Data shows that for most dogs the length of time they are immune following vaccination for Leptospirosis is less than 18 months and often closer to 12 months. If your pet runs over the due date for their leptospirosis vaccine by more than a few months it is necessary to give the full primary course of two vaccinations again. This is to ensure they are fully protected.

Can a dog have sufficient levels of immunity that mean they do not need to restart their vaccines?

For the viral diseases (CDV, CPV and CAV) this is a simple matter of measuring antibody levels on a blood test. There is a pretty good correlation between high antibody levels and adequate protection against disease. So we know we can allow these pets to go over their normal vaccination interval. However, this is not the case with Leptospirosis. When antibody levels drop very quickly after vaccination and are in any case not good at predicting whether your pet is protected. This is another reason why your vet will recommend restarting the course of Leptospirosis vaccines if they have lapsed for a certain period of time.

Success of dog vaccination programmes

Many of the diseases we vaccinate against have become rare. However, they have not disappeared. It is important that our dogs are kept up to date with their vaccinations. This is to give them the best possible protection against these serious illnesses. Thankfully vaccination complications are very rare. But if you have any concerns or questions about your pet’s vaccinations your veterinary surgeon will be very happy to answer them.

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